caustic surface

noun

: the cusped surface of maximum brightness that is sometimes observed when light is refracted or reflected by a curved mirror or interface and is geometrically the envelope of the system of refracted or reflected rays

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now